It is the long-range purpose of this project to study the biochemical and pharmacological basis of mood, especially euphoria. Topics under study at present are: What mood alterations are induced by drugs of abuse such as cocaine and amphetamine? Do lithium or alpha-methyl-para-tyrosine (AMPT) block the euphoria of cocaine or amphetamine? Do lithium or AMPT block the euphoria of morphine or alcohol? What are the links between opiate, analgesics and mood? Do opiate antagonists such as naloxone have distinct mood effects? Do narcotic antagonists have potential in the treatment of the affective illnesses?